This is a cell phone camera of what appear to be a pair of parallel vapor trails in a cloud chamber (a saturated ethanol environment over dry ice.) The question is, what accounts for the parallel tracks which seem to be visible in the image? Is the one an optical reflection of the other? Made how? (The light source is a slide projector set up just to the right of the image, behind a plexiglass wall.) If not a reflection, then what accounts for the two parallel tracks? A nearby common source should have produced events with a common vertex, and thus the only angle from which the lines would appear parallel would be looking down through one line into the other, but that’s not the case here (though perhaps it’s close to that.) Any ideas? The full original image is below.
